Conditioning minerals for film concentration



Patented May 31, 1949 OFFICE CONDITIONING DIINERALS FOR FILM CONCENTRATION John Dasher, Galveston, Ten, and James E. Norman, Malvern, Ark.

No Drawing. Application January 11, 1945, Serial No. 572,441

3 Claims. (Cl. 209-9) This invention relates to the concentration of minerals-by flotation or other filming processes,-

and more particularly to a method whereby results by these processes are generally improved, and in particular are such results enhanced on diflicult ores that are resistant to normal methods of separation.

In the filming process methods of minerals separation the purpose is to effect as nearly perfect separation as possible of a mineral or group of minerals from another mineral or group of minerals. Perfect separations are never obtained, so for each common separation a standard is accepted. I

The primary object of the present invention is to provide a method which not only gives above the standard separations on normal ores, but

also permits standard results to be obtained on diflicult ores which are resistant to normal methods.

In treating normal ores each increment of collector results in an increase in the recovery of the minerals being collected, but a point is reached when the proportion of undesired minerals which are collected becomes excessive. Hence higher recoveries are not profitable by normal methods. With some mineral mixtures, especially weathered ores, or materials containing a high proportion of slime, collector additions result in no appreciable increase in recovery even when recovery of desired minerals is incomplete. Instead, undesired minerals will be collected, and hence the efliciency of the process deteriorates.

'In accordance with the present invention it has been found that the deficiency just indicated may be remedied by conditioning the pulp with the collector at a temperature above normal operat: ing temperatures. The greater the temperature, the greater the effect produced. We, therefore, prefer to use a hot pulp, namely, one above 50 C. This conditioning, however, is done on a thick pulp of a density higher than that normally used in froth flotation, or fed to agglomerating tables or other concentrating equipment.

Conditioning of the pulp as just indicated consists in agitating the hot pulp with the modifying and/or collecting reagents. The degree of agitation, similar to the degree in the conditioning temperature, is important, results being enhanced from intense agitation during the heating period. At the termination of the conditioning period the conditioned pulp is then diluted with unheated liquid such as used in normal concentration methods and is then subjected to the usual separation operations.

The hot conditioning of the present invention is superior to conducting the separation in a heated pulp in that it not only eflfects heat economy by decreasing the amount of liquid to be heated, but also it usually gives a more selective separation than is obtainable by flotation in a hotpulp.

Below are given specific examples 01' the effect of hot conditioning in accordance with the invention. Results are given where the only known difference in treatment is that one test was made by using a heated pulp in the conditioning step, while the other test was made with conditioning at room temperature.

Example 1 A sample of flotation concentrates, containing cassiterite (tin oxide) and tungsten minerals including wolframite and scheelite, was dried and shipped for further concentration by magnetic methods. These were not successful because the scheelite was lost with the tin. This treatment is very detrimental to subsequent flotation separation. Nevertheless, samples were conditioned at room temperature and at C. with 15 pounds per ton caustic soda and 2 pounds per ton oleic acid which is an example of a higher fatty acid, for twenty minutes, and floated with the addition of lime slurry to precipitate excess collector and prevent a foamy froth. The froth on the hot test was good, but the cold test gave a froth that could not be controlled well by the lime addition. The rougher froth was cleaned twice in alkaline pulp with lime added.

Assay, Distribution, wt. Per Per Cent Per Cent Product Cent W0; Sn W0; Sn

Hot

W Conc 33. 3 47. 0 l3. 0 64. 4 13. 9 6.7 16.0 29.3 4.4 7.0 l3. 3 l5. 0 34. 5 8. 2 l6. 2 46. 7 ll. 9 38 0 23. 0 62. 9

100. 0 24. 3 28. 2 1(1). 0 100. 0 C old:

47. 4 34. 9 22. 0 64. 5 37. 3 ll. 2 20. 5 33. 2 9. 0 13. 3 13. 0 l8. 0 33. 4 9. l 15. 9 28. 4 l5. 7 32. 5 l7. 4 33. 5

Example 2 Slimes decanted from the residue of acid leaching low-grade tin concentrates contain coke, elemental sulfur, undecomposed iron sulfides and a 'trace of copper sulfidw. A sample of pulp was filtered and washed slightly on the filter to remove the bulk of the spent acid and iron salts. It was divided and half conditioned at 70 C., and

4 Both samples were diluted with unheated water, 2% pounds per ton of sulfuric acid was added, and then they were floated. Results follow:

Example 4 In the flotation of a particularly refractory bauxite, normal methods gave no separation between the aluminum hydrates and the clay. Two samples were conditioned with pounds per ton caustic soda, 1 pound per ton sodium silicate, and 7.5 pounds per ton oelic acid for 5 minutes, the first at room temperature, and the second at half at room temperature, with 2 pounds per ton 5 Treatment Product w p per c Per sodium silicate and 0.4 pound per ton of, a com- Gent s10, Cent pound pine reagent which serves as a froth toughener for ten minutes. Pulps. were diluted at Concentrate 722 124 71.9 7 Room Temperaamn 27 8 13 6 28.1 mm water at room temperature and floated. tore. The froth was cleaned once with no further addi- 10 10M 10M tion of reagent. 0 mm 53 2 9 6 s 5 oncen Cond1ti0n0dat70C 4&8 m8 M5 Am Distrib a Per wt" 3 100.0 14.42 100.0 Product Per cent 311 011 s Sn Cu 8 Example 5 H t In the flotation of hematite from quartz in an M5 no L4 3L0 65,0 extremely slimy mixture, which contained no Middling 7.7 19.4. .10 7.61 a7 10.9 19.5 hematite coarse enough to be recovered on tables 58.1 15.5 miderflwr 1&1 05 55 89 9 and no quartz coarser than 200 mesh, the follow- 0 W 100- 10110 1001) loll-0 ing comparison was made. Two samples were 0 done 11.5 0.31 .06 13.2 4.4 123 07.3 Conditioned in a thick pulp for 5 minutes with 5 Middlh 81 101 pounds per ton oleic acid and no other reagent .4 70.1 16.1 1 Umtmw" 45 85 one at room temperature, the other at 60 C.

100.0 11.2 .057 223 100-0 10(1-0 1011-0 They were then diluted to proper flotation density and floated without the addition of any re- Erample 3 agent. Three samples of leached tin slimes were obtained from the waste acid siphoned from suc Treatment Product f g gg f cessive leaches of low'grade tin ore concentrates. Due tofifierenfzes. m slPhomng the grade and Conditioned at Concentrate 27.3 48.2 60.0 proport1on of shmes varied. These samples were Room Tempera- Middling.-- 14.5 11.7 7.8 conditioned ten minutes with 7 pounds per ton F Talmgmm m7 sodium silicate, the first at room temperature, 100.0 21.9 100.0 the other two at 70 C. Sulfur, sulfides and poke concentrate V 2&9 4 us were floated with 0.4 pound per ton of a compound Conditioned at 00 0. Middling.-. 11.9 15. 7 9. 0 pine reagent which serves as a froth toughener, Tahng 6L2 and cleaned once. The non-floats were deslimed 100.0 20.3 100.0 by settling and decantation so that no cassiterite grains coarser than 2 microns were lost. The seth nti n l d tled fraction was conditioned w t 2 pounds P9 1. The process of concentrating a cassiterite ton oleic acid for 10 minutes, the first two tests mineral mixture which comprises, forming a thick at room emp r ture, a d the third test at pulp containing the minerals to be separated, QThe object of these tests was to obtain a tallelevating the temperature of the pulp to subrmgthat could be reJected. stantially 50 centigrade, agitating the heated Wt.1er Percent Dist. Treatment Product cent Sn Per cent Sulfides 4.6 8.36 2.1 Coneentrate. 21.5 52.58 63.1 Cold with sodium silicate, cold with oleic Middling 9.0 6. 84 3.4 'lailing 49.6 5.20 10.2 -2 Mn sum6 15.2 13.00 15.2

sulfides 7.1 6.25 2.0 Concentrate 27. 4 55. 45 73. 9 Hot with sodium silicate, cold with oleic Middling 5.6 13.47- 3.!) Telling.--" 44.1 4.23 0.1 -2 Mu Slime.. 15. a 14. 67 11.3

7.3 3.06 1.6 28.5 35.77 73.3 Hot with sodium silicate, hot with oleic 7. 6 4. 22 2.3 35.0 .63 1.6 20.0 13.64 21.2

pulp in the presence of a higher fatty acid collector reagent, adding unheated liquid to the hot pulp, and thereafter selectively separating the filmed mineral from the gangue,

2. The process of concentrating a bauxite mineral mixture by filming processes comprising, applying heat to a thick pulp, subjecting the heated C. pulp to agitation in the presence of a higher fatty 5 acid collector reagent, adding water to the pulp, and subjecting the resultant pulp to a filming process of separation.

3. The process of concentrating a cassiterite mineral mixture by filming processes comprising I treating a thick pulp of the mineral mixture including oleic acid by elevating the temperature of said pulp therein to approximately 50 centigrade, agitating the pulp while at the elevated temperature, diluting the pulp with a liquid including a precipitant for excess oleic acid, and subjecting the resultant pulp to flotation process to recover the desired minerals from the pulp.

JOHN DASHER. JAMES E. NORMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Sulman Nov. 6, 1906 Number OTHER REFERENCES 15 Taggart Handbook of Mineral Dressing-1945,

' pages 1,218, 1,219, 1,299.

Gaudin Principles of Mineral Dressing, 1939, pages 403, 404. 

